1. Field of the Invention
The present invention relates to a transported-object stacking apparatus.
2. Description of the Related Art
Conventionally, in a transported-object stacking apparatus for stacking sheetlike transported objects one by one, a high-speed conveyor running at high speed and a low-speed conveyor running at low speed are arranged adjacent to each other, while a speed-reducing section is provided at the entrance of the low-speed conveyor. Objects transported on the high-speed conveyor are reduced in speed during transfer to the low-speed conveyor and are stacked on the low-speed conveyor.
However, in the conventional transported-object stacking apparatus, the front end of an object transported at high speed by the high-speed conveyor may collide with a rear portion of the preceding object transported at low speed by the low-speed conveyor, potentially resulting in jamming of transported objects.
Since the angle of a transported object entering the speed-reducing section, i.e., the angle of entry, is difficult to adjust, the preceding transported object may be hit hard by the front end of the following transported object. As a result, the surface of the preceding transported object may be damaged, rendering the object defective. Particularly, when a transported object is lightweight, the transported object enters the speed-reducing section at a relatively high speed. As a result, the posture of the transported object becomes very unstable during entry into the speed-reducing section.
To avoid such a postural instability, an object may be transported while being held between the high-speed conveyor and a guide belt running at a speed identical to that of the high-speed conveyor. However, this causes variations in, for example, positioning or timing curing transfer of a transported object from the high-speed conveyor to the low-speed conveyor.
To avoid such variations, the traveling speed of the high-speed conveyor may be decreased, or the span between transported objects may be increased. In such a case, however, the throughput of the transported-object stacking apparatus is impaired accordingly.